Barbiturates and Analgesics in Calliphora vicina Larvae

Abstract

Calliphora vicina larvae were reared on artificial foodstuffs spiked with a range of concentrations of aspirin (acetylsalicylic acid), sodium salicylate, paracetamol, sodium aminohippurate, amphetamine sulfate, and the barbiturates thiopentone, phenobarbitone, amylobarbitone, barbitone, and brallobarbitone. Larvae were harvested at either day 6, 7, or 8 for analysis of drug content. Paracetamol, aspirin, amylobarbitone, and thiopentone were not detected in larvae fed on foodstuff containing drug concentrations equivalent to those expected in skeletal muscle from fatal human overdoses. Drug concentrations in larvae (expressed as larva: Foodstuff drug ratio) were 12–14% for phenobarbitone, 9–11% for sodium salicylate, 10% for aminohippurate, 18–19% for brallobarbitone, 41% for amphetamine, and 50–67% for barbitone. Amylobarbitone became detectable in larvae fed on higher drug concentrations (larva: Foodstuff drug ratio 2.6–21%). Higher levels of thiopentone and phenobarbitone were lethal to the larvae. Despite sharing similar basic structures, related drugs were each handled very differently by the larvae. We found it impossible to predict, on the basis of chemical structure, which drugs are likely to be detectable in Calliphora vicina larvae and in what ratio to the drug-spiked foodstuff. Drug concentrations in larvae are significantly lower than in their food source and the absence of a drug from feeding larvae does not necessarily imply its absence from the food source.

Forensic entomology

“…The toxicological analysis of Calliphora vicina larvae reared on a substrate containing four benzodiazepines yielded a negative result for the rapidly eliminated loprazolam, although bromazepam and diazepam were detected (Sadler et al 1997b). Larval drug and food source concentrations differed in an unpredictable ways and were found not to be useful for quantitative calculations.…”

“…The usefulness of entomotoxicological methods has been demonstrated in experimental (e.g. Introna et al 1990;Sadler et al 1997a;Goff et al 1997;Hedouin et al 2001;Pien et al 2004) as well as miscellaneous case studies (e.g. Beyer et al 1980;Kintz et al 1994;Sadler et al 1995).…”

“…The absence of a drug in larvae may not indicate that the drug was not present in the food source (Sadler et al 1997a(Sadler et al , 1997b(Sadler et al , 1997c. The toxicological analysis of Calliphora vicina larvae reared on a substrate containing four benzodiazepines yielded a negative result for the rapidly eliminated loprazolam, although bromazepam and diazepam were detected (Sadler et al 1997b).…”

The detection of toxic substances in entomological specimens

“…Following the work of Beyer et al [9], demonstrating the presence of phenobarbital in larvae found on a skeletonised female body, numerous experiments were carried out by other groups [10,11,12,13,14,15,16,20,21,23,24] to detect controlled substances and drugs (e.g. opiates, benzodiazepines, antidepressants, cocaine, acetylsalicylic acid and amphetamine derivatives) and to gain useful information on the cause of death, when the toxicologist was unable to examine the usual biological fluids and tissues.…”

“…In 1980, the first article about a drug, phenobarbital, was published by Beyer et al [9]. In entomological cases, other authors have also analysed drugs and narcotics, in particular triazolam, oxazepam, phenobarbital, alimemazine, clomipramine [10], bromazepam, levomepromazine and clomipramine [11], morphine and phenobarbital [12], cocaine [13,14], amitriptyline, propoxyphene and acetaminophen [15], opiates [16,17,18,19], amitriptyline and nortriptyline [20,21,22], amitriptyline, temazepam, trazodone and trimipramine [23], salicylates, paracetamol, aminohippurate, amphetamines and barbiturates [24], and amphetamine derivatives [25].…”